Heavy metal (often referred to simply as metal) is a genre of rock music[1] that developed in the late 1960s and early 1970s, largely in England and the United States.[2] With roots in blues-rock and psychedelic rock, the bands that created heavy metal developed a thick, massive sound, characterized by highly amplified distortion, extended guitar solos, and emphatic beats. Allmusic states that "of all rock & roll's myriad forms, heavy metal is the most extreme in terms of volume, machismo, and theatricality".[3]
Early heavy metal bands such as Led Zeppelin, Black Sabbath, and Deep Purple
attracted large audiences, though they were often critically reviled, a
status common throughout the history of the genre. In the mid-1970s, Judas Priest helped spur the genre's evolution by discarding much of its blues influence; Motörhead introduced a punk rock sensibility and an increasing emphasis on speed. Bands in the New Wave of British Heavy Metal such as Iron Maiden followed in a similar vein. Before the end of the decade, heavy metal had attracted a worldwide following of fans known as "metalheads" or "headbangers".
In the 1980s, glam metal became a major commercial force with groups like Mötley Crüe. Underground scenes produced an array of more extreme, aggressive styles: thrash metal broke into the mainstream with bands such as Metallica, while other styles like death metal and black metal remain subcultural phenomena. Since the mid-1990s, popular styles such as nu metal, which often incorporates elements of funk and hip hop; and metalcore, which blends extreme metal with hardcore punk, have further expanded the definition of the genre.
Heavy metal is traditionally characterized by loud distorted
guitars, emphatic rhythms, dense bass-and-drum sound, and vigorous
vocals. Metal subgenres variously emphasize, alter, or omit one or more
of these attributes. The New York Times critic Jon Pareles
writes, "In the taxonomy of popular music, heavy metal is a major
subspecies of hard-rock—the breed with less syncopation, less blues,
more showmanship and more brute force."[4] The typical band lineup includes a drummer, a bassist, a rhythm guitarist, a lead guitarist, and a singer, who may or may not be an instrumentalist. Keyboard instruments are often used to enhance the fullness of the sound.[5] The loud, distorted Hammond organ and occasionally the magnetic tape-based mellotron were popular with early metal bands; these instruments were displaced in the 1980s by electronic keyboard synthesizers. Today, keyboards are used in styles such as progressive metal, power metal, and symphonic metal. Some nu metal bands incorporate hip hop elements, which may include a DJ scratching and creating various sound effects.
The electric guitar and the sonic power that it projects through amplification has historically been the key element in heavy metal.[6] Guitars are often played with distortion pedals through heavily overdriven tube amplifiers to create a thick, powerful, "heavy" sound. In the early 1970s, some popular metal groups began cofeaturing two guitarists. Leading bands such as Judas Priest and Iron Maiden
followed this pattern of having two or three guitarists share the roles
of both lead and rhythm guitar. A central element of much heavy metal
is the guitar solo, a form of cadenza. As the genre developed, more intricate solos and riffs became an integral part of the style. Guitarists use sweep-picking, tapping, and other advanced techniques for rapid playing, and many styles of metal emphasize virtuosic displays.
The lead role of the guitar in heavy metal often collides with the
traditional "frontman" or bandleader role of the vocalist, creating a
musical tension as the two "contend for dominance" in a spirit of
"affectionate rivalry".[5]
Heavy metal "demands the subordination of the voice" to the overall
sound of the band. Reflecting metal's roots in the 1960s
counterculture, an "explicit display of emotion" is required from the
vocals as a sign of authenticity.[7] Critic Simon Frith claims that the metal singer's "tone of voice" is more important than the lyrics.[8] Metal vocals vary widely in style, from the multioctave, theatrical approach of Judas Priest's Rob Halford and Iron Maiden's Bruce Dickinson, to the gruff style of Motörhead's Lemmy and Metallica's James Hetfield, to the straight-out screaming and growling At the Gates' Tomas Lindberg, to the phlegm-clogged, possessed style of black metal singers such as Mayhem's Dead.
The prominent role of the bass is also key to the metal sound, and the interplay of bass and guitar is a central element.[9] The bass guitar provides the low-end sound crucial to making the music "heavy".[10] Metal basslines vary widely in complexity, from holding down a low pedal point as a foundation to doubling complex riffs and licks along with the lead and/or rhythm guitars. Some bands feature the bass as a lead instrument,[9] an approach popularized by Metallica's Cliff Burton in the early 1980s.[11] Metal bassists frequently use picks instead of fingerstyle plucking, to get a stronger, clearer articulation. A few use shred guitar–style
techniques such as tapping and sweep picking. In some styles, such as
thrash and death metal, the bass may be distorted with a bass overdrive
pedal for a heavier, thicker sound. Nu metal as well as death metal
bassists often use a five- or six-string bass (or a detuned instrument)
with an extended lower range.
The essence of metal drumming is creating a loud, constant beat for
the band using the "trifecta of speed, power, and precision".[12]
Metal drumming "requires an exceptional amount of endurance", and
drummers have to develop "considerable speed, coordination, and
dexterity...to play the intricate patterns" used in metal.[13] A characteristic metal drumming technique is the cymbal choke,
which consists of striking a cymbal and then immediately silencing it
by grabbing it with the other hand (or, in some cases, the same
striking hand), producing a burst of sound. The metal drum setup is
generally much larger than those employed in other forms of rock music;[10] in some cases, a "huge drum kit envelope[s] the whole of the backline" of the stage.[14]
Aside from the standard toms, bass drum, snare, and hi-hat, ride, and
crash cymbals used in many rock drumkits, there is often a double bass
drum, additional toms, a number of additional cymbals (e.g., splash and
extra crash cymbals), and other instruments such as a cowbell.
In live performance, loudness—an "onslaught of sound," in Deena Weinstein's description—is considered vital.[6] In his book Metalheads, Jeffrey Arnett refers to heavy metal concerts as "the sensory equivalent of war."[15] Following the lead set by Jimi Hendrix, Cream and The Who, early heavy metal acts such as Blue Cheer set new benchmarks for volume. As Blue Cheer's Dick Peterson puts it, "All we knew was we wanted more power."[16]
Reviewing a Motörhead concert in 1977, Paul Sutcliffe noted how
"excessive volume in particular figured into the band’s impact."[17] Weinstein makes the case that in the same way that melody is the main element of pop and rhythm is the main focus of house
music, powerful sound, timbre, and volume are the key elements of
metal. She argues that the loudness is designed to "sweep the listener
into the sound" and to provide a "shot of youthful vitality."[6] Heavy metal's fixation on loudness was mocked in the rockumentary spoof This Is Spinal Tap, in which a metal guitarist claims to have modified his amplifiers to "go to eleven."
Musical language
Rhythm and tempo
The beat in metal songs is emphatic, with deliberate stresses.
Weinstein observes that the wide array of sonic effects available to
metal drummers enables the "rhythmic pattern to take on a complexity
within its elemental drive and insistency."[10]
In many heavy metal songs, the main groove is characterized by short,
two-note or three-note rhythmic figures—generally made up of 8th or 16th notes. These rhythmic figures are usually performed with a staccato attack created by using a palm-muted technique on the rhythm guitar.[18]
An example of a rhythmic pattern used in heavy metal.
Brief, abrupt, and detached rhythmic cells are joined into rhythmic
phrases with a distinctive, often jerky texture. These phrases are used
to create rhythmic accompaniment and melodic figures called riffs, which help to establish thematic hooks. Heavy metal songs also use longer rhythmic figures such as whole note- or dotted quarter note-length chords in slow-tempo power ballads. The tempos in early heavy metal music tended to be "slow, even ponderous."[10]
By the late 1970s, however, metal bands were employing a wide variety
of tempos. In the 2000s, metal tempos range from slow ballad tempos
(quarter note = 60 beats per minute) to extremely fast blast beat tempos (quarter note = 350 beats per minute).[13]
Harmony
One of the signatures of the genre is the guitar power chord.[19] In technical terms, the power chord is relatively simple: it involves just one main interval, generally the perfect fifth, though an octave may be added as a doubling of the root. Although the perfect fifth interval is the most common basis for the power chord,[20] power chords are also based on different intervals such as the minor third, major third, perfect fourth, diminished fifth, or minor sixth.[21]
Since the power chord is based on a single interval, it enables
guitarists to use a high level of distortion without unintended inharmonicity or intermodulation distortion. If a triad—a
chord with a root, third, and fifth—is played on a heavily distorted
guitar, intermodulation distortion may produce frequency components at
the various sums and differences of the frequency components of the
input signal which will be not be harmonically related to the input
signal, leading to disarmonious sounds.[22] Most power chords are also played with a consistent finger arrangement that can be slid easily up and down the fretboard.[23]
